This simulated view from NASA's Cassini spacecraft shows the expected positions of Saturn and Earth on July 19, 2013, around the time Cassini will take Earth's picture. Cassini will be about 898 million miles (1.44 billion kilometers) away from Earth at the time. That distance is nearly 10 times the distance from the sun to Earth. Image credit: NASA/JPL-Caltech

Special Wave at Saturn Edition: Friday (July 19) will be the first time in history Earthlings have had advance notice their picture was being taken from deep space.

1. WHO?

You and everyone you know. NASA is asking everyone to stop what they doing and wave toward Saturn on Friday, July 19 between 5:27 and 5:42 p.m. EDT (2:27 to 2:42 p.m. PDT or 21:27 to 21:42 UTC). Take a picture of your Saturn salute and share it on your favorite social media site with the hashtag #WaveAtSaturn.

Cassini will be able to see the whole Saturn system backlit by the sun on July 19. It's a great science opportunity and it makes a beautiful picture - one that happens to have Earth in the background as well.

Cassini's image of Earth will be just 1.5 pixels wide, with the illuminated part of Earth less than a pixel, so the resulting mosaic will not actually show people or the continents. But if you are on the sunlit side of Earth at the time - North America and part of the Atlantic Ocean -- you are in the picture.

For those in the western U.S., step outside (or stay inside) and wave low on your eastern horizon. Wave southeast in the central and eastern U.S. as Cassini's cameras take a series of pictures over about 15 minutes

Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini's highest-resolution camera.